Improvement in Resistance Performance on High Block Coefficient Hulls with Air Lubrication

Artificial air cavities are proposed for their use on high block coefficient hulls, navigating at low speeds, to reduce their resistance. The air lubrication reduces the friction resistance and, consequently, the ship total resistance. This result will be demonstrated through a series of experiments carried out by many researchers and by the author too [1]. The hull models of a tanker and of a dredger have been modified, by creating artificial cavities on the bottom. The models have been tested at the DINMA laboratories of the University of Trieste and the physical phenomena arising from the cavities generation and their development have been investigated by using submerged cameras. From these measures and the images reproducing the cavity growth, it is possible to search the appropriate geometrical solution to reduce the ship resistance. The results obtained are encouraging, but require new tests for the hull optimization.